Pros

Pro

Easy to skim through content

AlternativeTo makes it easy to quickly find stuff. The lists are organized by likes which floats the best content to the top, and helpful tags warn you of undesirable attributes (such as the product being discontinued or if it includes bundleware).

Pro

Filtering and sorting capabilities

The ability to filter by platform and license means that you can easily filter out software that you can't use. More specific filters and sort orders are also available.

Pro

Comprehensive

Full website with lot's of content, info, users, comments, etc. Value for free.

Cons

Con

Limited details available on the site itself

AlternativeTo excels at showing you options, however it doesn't really tell you why one option is better/worse than another. It lists options by the number of likes it has received, but to directly compare the options is relatively hard to do.